Data hygiene

I talk about data hygiene with clients a lot. In my experience, poor data hygiene is the number one reason that legitimate, permission based marketing ends up in the junk folder. Too many marketers don’t remove abandoned addresses from their mailing lists. As the abandoned addresses build up, eventually the list accumulates enough zombie addresses that it looks similar to a spammer’s list.
I’ve talked in depth about zombie accounts previously (part 1, part 2, part 3, apocalypse) and they talk a lot more about why we have zombies accounts and why they’re just starting to be a bigger issue for marketers. Not only are we just starting to hit critical mass with zombie accounts, but ISPs are really starting to weigh engagement in their delivery decisions. Zombie accounts are not engaged with mail. Heck, they’re not even engaged with their own email addresses.
Many marketers, though, hate the idea of data hygiene. They hate thinking about losing a potential customer. They can show me numbers that say someone didn’t open an email for 18 months and then spent hundreds of dollars on a purchase. Or they can tell me that 10% of their revenue came from people who hadn’t opened an email in more than 12 months.
I don’t want to take those subscribers away from you, the ones who are engaged with your brand or your mail in some un-trackable way. But I do want to stop the zombies from eating your delivery.

Gathering data at subscription time
Data hygiene and bouncing zombies

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Zombie email: Part 3

Last week, in Zombie email: part 1 and part 2 I talked a little about the history of email addresses and how changes in the ISP industry in the early to mid 2000’s brought about the rise of zombie email addresses. Today we’ll look at the effect zombie addresses have on email stats and why ISPs are starting to monitor zombie addresses.
A zombie address, despite the fervent belief of some email marketers, doesn’t come back to life. The person who initially registered that address has decided to stop using that email address.  The defining factor of a zombie address is that there isn’t now and won’t be anyone in the future reading email sent to that address. There is no human there to read or react to any email sent to that address.
A zombie address does not represent an actual recipient, they’re just remnants of a recipient that once was present.
Having a list containing any significant number of zombie addresses can throw off metrics enough to mislead a sender about the effectiveness of their email marketing program. Sometimes, the zombie addresses make the metrics look worse, sometimes they make metrics look better. In either case, the metrics don’t accurately represent the performance of a marketing program.
Zombie email addresses do bulk out a mailing list, making lists look bigger. They’re not real addresses, so they don’t reflect quality, but they do impress marketers that think bigger is always better. But, in reality, you may as well add thousands of addresses at non-existent domains for the real value these addresses bring to your list.
Zombie email addresses on a list depresses any metric that use “number of emails sent” or “number of emails accepted” as a denominator.  If 10% of a list is zombie addresses, then an open rate reported as 15% will actually be an open rate of 16.7%. The more zombie addresses on a list, the more the statistics will be depressed.
In addition to having lower open rates, lists with more zombie addresses also have a lower complaint rate. In fact, in the recent past spammers have padded their lists with zombie addresses as a way to artificially lower their complaint rates.
Spammers using addresses created just to bulk up the denominator and lower complaint rates have led ISPs to start monitoring the types of addresses on a particular list. I first heard about ISPs looking at recipient profiles at a meeting in 2006, so it is not, in any way, a new technique for ISPs. What is new is the number of zombie addresses on legitimate, well maintained lists, and the fact that they are present in high enough volume to affect reputation and delivery.
ISPs use zombie addresses to monitor the reputation of a sender because it is a more accurate way to measure what the recipients think about an email and that sender. Senders ignore zombie addresses because they make some stats look bigger (total list size) and better (lower complaint rates). Many senders also believe that addresses come back to life, despite all evidence to the contrary, and will not purge an address for any reason other than it bounces. They’d rather live with inaccurate and misleading metrics than removing non-performing addresses.
Tomorrow, in the final post of this series, we’ll examine how senders can identify potential zombie addresses and what steps they can take protect themselves from the negative reputation hit from zombie addresses. (Zombie Apocalypse)

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Don't take my subscribers away!

Tom Sather has a good summary of the problems with inactive email addresses and why data hygiene is critical to maintain high deliverability. These recommendations are some of the most difficult to convince people to implement.
Some of my clients even show me numbers that show that a recipient that hadn’t opened or read and email in 18 months, suddenly made a multi-hundred dollar purchase. Another client had clear numbers that showed even recipients that didn’t open for an entire year were responsible for 10% of revenue.
They tell me I can’t expect them to let their customers go. These are significant amounts of money and they won’t let any potential revenue go without a fight.
I understand this, I really do. The bottom line numbers do make it tough to argue that inactive subscribers should be removed. Particularly when the best we can offer is vague statements about how delivery may be affected by sending mail to unengaged users.
I don’t think many senders realize that when they talk about unengaged users they are actually talking about two distinct groups of recipients.
The first group is that group of users that actively receive email, but who aren’t opening or reading emails from particular senders. This could be because of their personal filters, or because the mail is going to the bulk folder or even simply because they don’t load images by default. This is the pool that most senders think of when they’re arguing against removing unengaged users.
The second group is that group of users that never logs in ever. They have abandoned the email address and never check it. I wrote a series of posts on Zombie Emails (Part 1, 2, 3) last September, finishing with suggestions on how to fight zombie email addresses.
Unlike senders ISPs can trivially separate the abandoned accounts from the recipients who just don’t load images. Sending to a significant percentage of zombie accounts makes you look like a spammer. Not just because spammers send mail to really old address lists, but a number of spammers pad their lists with zombie accounts in order to hide their complaint rates. The ISPs caught onto this trick pretty quickly and also discovered this was a good metric to use as part of their filtering.
I know it’s difficult to face the end of any relationship. But an email subscription isn’t forever and if you try to make it forever then you may face delivery problems with your new subscribers.

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Zombie email: Part 2

In zombie email: part 1 I talked about how email addresses were tightly tied to internet access in the very early years of the internet. We didn’t have to worry about zombie email addresses because when an account was shut down, or ignored for a long time then mail would start bouncing and a sender could stop sending to that account.
There were two major changes to email accounts in the early 2000’s that led to the rise of zombie emails.
People started decoupling their internet access from their email addresses. Free addresses were easy to get and could be checked from everywhere. No longer did they have to dial in to get email, they could access it from outside the office and outside the home. Mobile devices, including the first generation of smart phones and laptops, helped drive people to use email addresses that they could access from any network. The easy access to free mail accounts and the permanence led people to adopt those addresses as their primary address.
When people changed addresses, for whatever reason, they didn’t have to stop paying. There was no way to tell the free ISPs to stop accepting mail for that address. Free mail providers would let addresses linger for months or years after the user had stopped logging in. Sometimes those addresses would fill up and start bouncing email, but they were not often turned off by the ISPs.
The lack of purging of abandoned addresses was the start of dead addresses accumulating on mailing lists. But there weren’t that many addresses in this state, and eventually they would fill up with mail. When they were full the ISP would stop accepting new mail for that account, and the address would bounce off a mailing list.
Everything changed with the entrance of Gmail onto the scene. When Gmail launched in 2004 they were providing a whole GB of storage for email accounts a totally unheard of storage capacity. Within a year they were providing multiple gigabytes of storage. Other freemail systems followed Gmail’s lead and now all free accounts have nearly unlimited storage. Plus, any mail in the spam folder was purged after a few weeks and bulk mail doesn’t count against the users’ storage quota. Now, an abandoned email account will almost never fill up thus senders can’t use over quota bounces to identify abandoned accounts.
Now we’re stuck in a situation where SMTP replies can’t be used to identify that there is no one home inside a particular email account. Senders can’t distinguish between a quiet subscriber and an abandoned address. ISPs, however, can and are using zombie addresses as a measure of a senders reputation.
On Monday we’ll talk about why and how zombie addresses can affect delivery. (Zombie emails: part 3)
Tuesday, we’ll talk about strategies to protect your list from being taken over by zombies. (Zombie Apocalypse)

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